Abstract: A method of controlling the time constant of a filter for use in a radio receiver which receives a signal, transmitted from a transmitting station at a predetermined period, intermittently at the predetermined period and demodulates and delivers the received signal, a filter circuit having the time constant control function based on the method, and a radio receiver having the filter circuit. Preferably, the filter has its time constant switchable stepwise and specifically, parallel connection of capacitors or shortcircuiting of resistors is controlled by turning on/off switches.

Abstract: In a method of driving a display panel including liquid crystal cells arranged in the form of a matrix and displaying such display information as pictures, characters and numerals, which applies scanning pulse voltages to lateral electrodes of the display panel and applies to longitudinal electrodes of the display panel voltages of the pulse width modulation corresponding to the information to-be-displayed, thus to perform the line progressive scanning, a driving method in which voltages in an address period and in a nonaddress period as applied to the longitudinal electrodes are symmetric in magnitude to a voltage in the nonaddress period as applied to the lateral electrodes, and the difference between voltages in the address period and in the nonaddress period as applied to the lateral electrodes is at least double the difference between the voltages in the address period and in the nonaddress period as applied to the longitudinal electrodes.